Method and Device for Encoding a High Frequency Signal, and Method and Device for Decoding a High Frequency Signal

1. A method for encoding a high frequency signal, comprising: determining a signal type of the high frequency signal of a current frame; when the high frequency signal of the current frame is non-transient and the high frequency signal of a previous frame is transient, smoothing and decreasing a time envelope of the high frequency signal of the current frame to obtain a processed time envelope of the high frequency signal of the current frame; and quantizing and encoding the processed time envelope, frequency information, and signal type information of the high frequency signal of the current frame, wherein the quantized and encoded signal type information indicates that the high frequency signal of the current frame is transient.

2. The method according to claim 1 , further comprising: when the high frequency signal of the current frame is transient, quantizing and encoding the time envelope, the frequency information, and the signal type information of the high frequency signal of the current frame.

3. The method according to claim 1 , further comprising: when both the high frequency signal of the current frame and the high frequency signal of the previous frame are non-transient, quantizing and encoding the frequency information, and the signal type information of the high frequency signal of the current frame.

4. The method according to claim 3 , further comprising: determining specific classes of the non-transient signal; and quantizing and encoding the specific classes of the non-transient signal.

5. The method according to claim 1 , wherein the smoothing and scaling the time envelope of the high frequency signal of the current frame to obtain the processed time envelope of the high frequency signal of the current frame comprises: forming the processed the time envelope of the high frequency signal of the current frame by combining a time envelope of the high frequency signal of a second half frame of the previous frame and a smoothed and scaled time envelope of the high frequency signal of a first half frame of the current-frame.

6. The method according to claim 1 , wherein the determining the signal type of the high frequency signal of the current frame comprises: dividing a full frequency or high frequency time domain signal of the current frame into at least two sub-frames; calculating energy information or amplitude information of each of the sub-frames; judging whether the energy information or amplitude information of a current sub-frame is greater than a first preset multiple of the energy information or amplitude information of a previous sub-frame, wherein the first preset multiple is greater than 1; and determining the high frequency signal of the current frame as a transient signal when the energy information or amplitude information of the current sub-frame is greater than the first preset multiple of the energy information or amplitude information of the previous sub-frame; and determining the high frequency signal of the current frame as a non-transient signal when the energy information or amplitude information of any sub-frames of the current frame is smaller than or equal to the first preset multiple of the energy information or amplitude information of a previous sub-frame of the sub-frame.

7. The method according to claim 6 , wherein before the determining the high frequency signal of the current frame as the transient signal, the method further comprises: calculating energy information or amplitude information of sub-frames in the first half frame of a next frame; obtaining minimum energy information or amplitude information from the energy information or amplitude information of all sub-frames that are behind a sub-frame of the current frame and the energy information or amplitude information of the sub-frames in the first half frame of the next frame, wherein the sub-frame has maximum energy information or amplitude information in the current frame; judging whether the energy information or amplitude information of the current sub-frame is greater than or equal to a second preset multiple of the minimum energy information or amplitude information, wherein the second preset multiple is greater than 1; and determining the high frequency signal of the current frame as the transient signal when the energy information or amplitude information of the current sub-frame is greater than or equal to the second preset multiple of the minimum energy information or amplitude information.

8. The method according to claim 6 , wherein before the determining the high frequency signal of the current frame as the transient signal, the method further comprises: judging whether a spectral tilt of the current frame is smaller than or equal to a first threshold value; and determining the high frequency signal of the current frame as a transient signal when the spectral tilt of the current frame is smaller than or equal to the first threshold value.

9. The method according to claim 1 , wherein the frequency information comprises frequency envelopes of the high frequency signal of the current frame, and the method further comprises: scaling the frequency envelopes of the high frequency signal of the current frame, before the quantizing and encoding the frequency information of the high frequency signal of the current frame; and quantizing and encoding the frequency information of the high frequency signal of the current frame, wherein the frequency information comprises the scaled frequency envelope of the high frequency signal of the current frame.

10. The method according to claim 1 , wherein the frequency information comprises global energy information or amplitude information of the high frequency signal of the current frame, and the method further comprises: scaling the global energy information or amplitude information of the high frequency signal of the current frame, before the quantizing and encoding the frequency information of the high frequency signal of the current frame; and quantizing and encoding the frequency information of the high frequency signal of the current frame, wherein the frequency information comprises the scaled global energy information or amplitude information of the high frequency signal of the current frame.

11. A method for encoding a high frequency signal, comprising: dividing a full frequency or high frequency time domain signal of a current frame into at least two sub-frames; calculating energy information or amplitude information of each of the sub-frames; calculating energy information or amplitude information of sub-frames in the first half frame of a next frame when the energy information or amplitude information of any one of the sub-frames of the current frame is greater than a first preset multiple of the energy information or amplitude information of a previous sub-frame of the sub-frame; obtaining minimum energy information or amplitude information from energy information or amplitude information of all sub-frames that are behind a sub-frame of the current frame and the energy information or amplitude information of the sub-frames in the first half frame of the next frame, wherein the sub-frame has maximum energy information or amplitude information in the current frame; judging whether the maximum energy information or amplitude information is greater than or equal to a second preset multiple of the minimum energy information or amplitude information, wherein the second preset multiple is greater than 1, and the first preset multiple is greater than 1; and determining a high frequency signal of a current frame as a transient signal when the maximum energy information or amplitude information of the sub-frame is greater than or equal to the second preset multiple of the minimum energy information or amplitude information, and quantizing and encoding time envelopes, frequency information, and signal type information of the high frequency signal of the current frame.

12. The method according to claim 11 , wherein before the determining the high frequency signal of the current frame as the transient signal, the method further comprises: judging whether a spectral tilt of the current frame is smaller than or equal to a first threshold value; and determining the high frequency signal of the current frame as the transient signal when the spectral tilt of the current frame is smaller than or equal to the first threshold value.

13. A method for encoding a high frequency signal, comprising: dividing a full frequency or high frequency time domain signal of a current frame into at least two sub-frames; calculating energy information or amplitude information of each of the sub-frames; judging whether a spectral tilt of the current frame is smaller than or equal to a first threshold value if the energy information or amplitude information of any one of the sub-frames of the current frame is greater than a first preset multiple of the energy information or amplitude information of a previous sub-frame of the sub-frame, wherein the first preset multiple is greater than 1; calculating energy information or amplitude information of sub-frames in a first half frame of a next frame; obtaining minimum energy information or amplitude information from the energy information or amplitude information of all sub-frames that are behind a sub-frame of the current frame and the energy information or amplitude information of the sub-frames in the first half frame of the next frame, wherein the sub-frame has maximum energy information or amplitude information in the current frame; judging whether the maximum energy information or amplitude information is greater than or equal to a second preset multiple of the minimum energy information or amplitude information, wherein the second preset multiple is greater than 1; and determining the high frequency time domain signal of the current frame as a transient signal when the maximum energy information or amplitude information is greater than or equal to the second preset multiple of the minimum energy information or amplitude information.

14. A device for encoding a high frequency signal, comprising: a determination unit, configured to determine a signal type of a high frequency signal of a current frame; and an encoding processing unit, wherein the encoding processing unit communicatively coupled to the determination unit, the encoding processing unit is configured to smooth and decrease time envelopes of the high frequency signal of the current frame, obtain time envelopes of the high frequency signal of the current frame to be encoded, when the determination unit determines that the high frequency signal of the current frame is a non-transient signal, but a high frequency signal of the previous frame is a transient signal, and quantize and encode the time envelopes of the high frequency signal of the current frame to be encoded, and frequency information and signal type information of the high frequency signal of the current frame, wherein signal type information of a transient signal is used when the signal type information of the high frequency signal of the current frame is quantized and encoded.

15. The device according to claim 14 , wherein the encoding processing unit is further configured to quantize and encode the time envelopes, the frequency information and the signal type information of the high frequency signal of the current frame when the determination unit determines that the high frequency signal of the current frame is transient.

16. The device according to claim 14 , wherein the encoding processing unit is further configured to quantize and encode the frequency information and the signal type information of the high frequency signal of the current frame, when the determination unit determines that both of the high frequency signal of the current frame and a high frequency signal of the previous frame are non-transient signals.

17. The device according to claim 14 , wherein the encoding processing unit is further configured to form the time envelopes of the high frequency signal of the current frame to be encoded with time envelopes of a second half frame of the previous-frame high frequency signal and the smoothed and scaled time envelopes of a first half frame of the-current frame high frequency signal after the time envelopes of the high frequency signal of the current frame is smoothed and scaled.

18. The device according to claim 14 , wherein the determination unit comprises: a division unit, configured to divide a full frequency or high frequency time domain signal of the current frame into at least two sub-frames; a calculation processing unit, configured to calculate energy information or amplitude information of each of the sub-frames of the current frame obtained by the division unit; a judgment unit, configured to judge whether the energy information or amplitude information of a current sub-frame calculated by the calculation processing unit is greater than a first preset multiple of the energy information or amplitude information of a previous sub-frame; wherein the first preset multiple is greater than 1; and a type determination unit, configured to determine that the high frequency signal of the current frame is transient when the judgment unit judges that the energy information or amplitude information of the current sub-frame is greater than the first preset multiple of the energy information or amplitude information of the previous sub-frame, and to determine that the high frequency signal of the current frame is non-transient when the judgment unit judges that the energy information or amplitude information of each sub-frame of the high frequency signal of the current frame is smaller than or equal to the first preset multiple of the energy information or amplitude information of a previous sub-frame of the sub-frame.

19. The device according to claim 18 , wherein the calculation processing unit is further configured to calculate energy information or amplitude information of sub-frames in the first half frame of a next frame, when the energy information or amplitude information of the current sub-frame is greater than the first preset multiple of the energy information or amplitude information of the previous sub-frame, and to obtain minimum energy information or amplitude information from the energy information or amplitude information of all sub-frames that are behind a sub-frame of the current frame and the energy information or amplitude information of the sub-frames in the first half frame of the next frame, wherein the sub-frame has maximum energy information or amplitude information in the current frame, wherein the judgment unit is further configured to judge whether the energy information or amplitude information of the sub-frame having the maximum energy information or amplitude information is greater than or equal to a second preset multiple of the minimum energy information or amplitude information found by the calculation processing unit, wherein the second preset multiple is greater than 1, and wherein the type determination unit is further configured to determine whether the high frequency signal of the current frame is transient when the judgment unit judges that the energy information or amplitude information of the current sub-frame is greater than the first preset multiple of the energy information or amplitude information of the previous sub-frame, and the energy information or amplitude information of the sub-frame having the maximum energy information or amplitude information is greater than or equal to the second preset multiple of the minimum energy information or amplitude information found by the calculation processing unit.

20. The device according to claim 19 , wherein the judgment unit is further configured to judge whether a spectral tilt of the current frame is smaller than or equal to a first threshold value when the energy information or amplitude information of the sub-frame having the maximum energy information or amplitude information is greater than or equal to the second preset multiple of the minimum energy information or amplitude information found by the calculation processing unit; wherein the type determination unit is further configured to determine whether the high frequency signal of the current frame is transient when the judgment unit judges that the energy information or amplitude information of the current sub-frame is greater than the first preset multiple of the energy information or amplitude information of the previous sub-frame, the energy information or amplitude information of the sub-frame having the maximum energy information or amplitude information is greater than or equal to the second preset multiple of the minimum energy information or amplitude information found by the calculation processing unit, and the spectral tilt of the current frame is smaller than or equal to the first threshold value.

21. The device according to claim 14 , wherein the frequency information comprises global energy information or amplitude information of the high frequency signal of the current frame, wherein the encoding processing unit is further configured to scale the global energy information or amplitude information of the high frequency signal of the current frame when the determination unit determines that the high frequency signal of the current frame is transient, and to quantize and encode the frequency information of the high frequency signal of the current frame having the scaled global energy information or amplitude information of the high frequency signal of the current frame.

22. The device according to claim 14 , wherein the frequency information comprises a frequency envelope of the high frequency signal of the current frame, wherein the encoding processing unit is further configured to scale the frequency envelope of the high frequency signal of the current frame when the determination unit determines that the high frequency signal of the current frame is transient, and to quantize and encode the frequency information of the high frequency signal of the current frame having the scaled frequency envelope of the high frequency signal of the current frame.

23. A device for encoding a high frequency signal, comprising: a division unit, configured to divide a full frequency or high frequency time domain signal of a current frame into at least two sub-frames; a calculation processing unit, configured to calculate energy information or amplitude information of each of the sub-frames, and energy information or amplitude information of sub-frames comprised in the first half frame of a next frame when a judgment unit judges that the energy information or amplitude information of any one of the sub-frames of the current-frame high frequency signal is greater than a first preset multiple of the energy information or amplitude information of a previous sub-frame of the sub-frame, and to obtain minimum energy information or amplitude information from the energy information or amplitude information of all sub-frames that are behind a sub-frame of the current frame and the energy information or amplitude information of the sub-frames in the first half frame of the next frame, wherein the sub-frame has maximum energy information or amplitude information in the current frame; the judgment unit, configured to judge whether the energy information or amplitude information of a current sub-frame calculated by the calculation processing unit is greater than the first preset multiple of the energy information or amplitude information of the previous sub-frame, and whether the energy information or amplitude information of the sub-frame having the maximum energy information or amplitude information is greater than or equal to a second preset multiple of the minimum energy information or amplitude information found by the calculation processing unit, wherein the second preset multiple is greater than 1, and the first preset multiple is greater than 1; a determination unit, configured to determine the high frequency signal of the current frame as a transient signal when the judgment unit judges that the energy information or amplitude information of the sub-frame having the maximum energy information or amplitude information is greater than or equal to the second preset multiple of the minimum energy information or amplitude information found by the calculation processing unit; and an encoding processing unit, configured to quantize and encode time envelopes, frequency information, and signal type information of the high frequency signal of the current frame when the determination unit determines that the high frequency signal of the current frame is transient.

24. The device according to claim 23 , wherein the judgment unit is further configured to judge whether a spectral tilt of the current frame is smaller than or equal to a first threshold value when the energy information or amplitude information of the sub-frame having the maximum energy information or amplitude information is greater than or equal to the second preset multiple of the minimum energy information or amplitude information found by the calculation processing unit, and wherein the determination unit is further configured to determine whether a high frequency signal of the current frame is transient when the judgment unit judges that the spectral tilt of the current frame is smaller than or equal to the first threshold value.

25. A device for encoding a high frequency signal, comprising: a division unit, configured to divide a full frequency or high frequency time domain signal of a current frame into at least two sub-frames; a calculation processing unit, configured to calculate energy information or amplitude information of each of the sub-frames of the current frame divided by the division unit, wherein the calculation processing unit is further configured to calculate the energy information or amplitude information of the sub-frames in a first half frame of a next frame when a judgment unit judges that a spectral tilt of the current frame is smaller than or equal to a first threshold value, and obtain minimum energy information or amplitude information from the energy information or amplitude information of all sub-frames that are behind a sub-frame of the current frame and the energy information or amplitude information of the sub-frames in the first half frame of the next frame, wherein the sub-frame of the current frame has maximum energy information or amplitude information in the current frame; the judgment unit, configured to judge whether energy information or amplitude information of any one of the sub-frames of the current frame calculated by the calculation processing unit is greater than a first preset multiple of energy information or amplitude information of a previous sub-frame, and whether a spectral tilt of the current frame is smaller than or equal to a first threshold value if the energy information or amplitude information of any one of the sub-frames of the current frame is greater than the first preset multiple of the energy information or amplitude information of the previous sub-frame of the sub-frame, wherein the first preset multiple is greater than 1, wherein the judgment unit is further configured to judge whether the energy information or amplitude information of the sub-frame having the maximum energy information or amplitude information is greater than or equal to a second preset multiple of the minimum energy information or amplitude information found by the calculation processing unit, and wherein the second preset multiple is greater than 1; a determination unit, configured to determine a high frequency signal of the current frame as a transient signal when the judgment unit judges that the spectral tilt of the current frame is smaller than or equal to the first threshold value and when the judgment unit judges that the energy information or amplitude information of the sub-frame having the maximum energy information or amplitude information is greater than or equal to the second preset multiple of the minimum energy information or amplitude information found by the calculation processing unit and an encoding processing unit, configured to quantize and encode time envelopes, frequency information, and signal type information of the high frequency signal of the current frame when the determination unit determines that the high frequency signal of the current frame is transient.